Electronic devices and circuitry, including 3D ICs and 3D SICs, generate excess heat and thus require thermal management to improve reliability and prevent premature failure. And, the amount of heat output corresponds to the power input of a device or circuit in general. Thus, temperature and power management of electronic devices and circuitry are closely related. There are many known technologies and combination of technologies for reducing the temperature of electronic devices and circuits, including many different types of heat sinks, cooling plates, passive systems, active systems (such as forced air systems and assemblies including fans), heat pipes, and many others. And, in cases of very low environmental temperatures, it may be necessary to keep the electronic components of devices and circuitry warm to achieve satisfactory operation and prevent premature damage and wear.
A 3D IC is an integrated circuit built by stacking silicon dies and interconnecting them vertically so that a combination of the dies is a single device. With a 3D IC, electrical paths through the device can be shortened by its vertically layout, which creates a device that can be faster and has a smaller footprint than similar ICs arranged side-by-side. 3D ICs can be generally grouped into 3D SICs, which refers to stacked ICs with through-silicon via interconnects (TSVs), and monolithic 3D ICs, which are generated using fabrication processes to realize 3D interconnects at the local levels of the on-chip wiring hierarchy as set forth by the International Technology Roadmap for Semiconductors (ITRS). Using the fabrication processes to realize the 3D interconnects can produce direct vertical interconnects between device layers. Monolithic 3D ICs are built in layers on a single wafer that is diced into separate 3D ICs.
3D SICs can be produced by three known general methods: a die-to-die, die-to-wafer, or a wafer-to-wafer method. In a die-to-die method, electronic components are generated on multiple dies. Then, the dies are aligned and bonded. A benefit of a die-to-die method is that each die can be tested before aligned and bonded with another die. In a die-to-wafer method, electronic components are generated on multiple wafers. One of the wafers can be diced and then aligned and bonded on to die sites of another wafer, accordingly. In a wafer-to-wafer method, electronic components are generated on multiple wafers, which are then aligned, bonded, and diced into separate 3D ICs.
A TSV is a vertical electrical connection that can pass through a die. TSVs can be a central part to increasing performance in 3D packages and 3D ICs. With TSVs, compared to alternatives for connecting stacked chips, the interconnect and device density can be substantially higher, and the length of the connections can be shorter.